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UNTEi srArEs PATENT Ormea;

" GEORGE H. coRnIss, or PROVIDENCE, RHODE IsnAND.

Specificaticn formingpart of Letters Patent No. 8,253, dated July `29, 1851; Reissued July 26,` i 185e, Nq. 7801 i To all whom it may concern Beit known that I, GEORGEH. CoRLIss,

Steam and Gas Engines; and,l doihereby declare that the following isafull, clear,` and exact description of thesame, reference being had tothe accompanying drawings, which form part `of this specification and'inwhich- Figure l represents a side elevation of a beam engine with myvalve-gear applied thereto; Figs. 2- and 3 are fragmentary sideelevations of the steam cylinder and valve-1 gear; `andligl 4 isasection of one of the valvechests andthe parts adjacent thereto.`

My improvement hasreference to `that class of cut-off valve motions inwhich the connection betweenthe valve and the eccentric or theequivalent thereof, which opens the valve, is broken to allow` the valveto move independently of the eccentric and close its steam portbeforethe piston has ccmpleted itsmstroke; and my Iimprovement consists ineifectingfthis disconnection of the valve and the eccentric gear, or theequivalent thereof,jby `imparting to the lift-4 ing roda lateralmovement whichislimited and Icontrolled by `an` adjustable stop andspring; so that the lifting rodnot only `performsthe duty usuallyimposed uponit of opening the valve but also performs the ofi'ice of acatch or` latch in connecting and disconnecting the valvewiththeeccentric In the accomp nying drawings A is the steamcylinderandB the crankshaft of the engine. The steam cylinder isfittedwith two side pipes C, D, which form the" valve chests in which thevalves are contained. That side pipe C farther from the crank shaft B,contains the steam valves 4and is connected with the steam pipe whichcon- Veys the steam from the boiler; theother side pipe containstheexhaust valves and is connected with the exhaust pipe through whichptheexhaust steam from the cylinder is discharged. `The steamu and exhaustvalves are in this instance of the `slidevai riety, each ismoved to open and close its-respective portsby an arm y which pro-j` jects from ashort rock shaft e.' These rock Shafts'fefend transversely thrashStufrig boxes in the sides` of their, respect-ive valve chests and theirprojecting extremities j are i fitted a a, b The arms a, a, of theexhaust valves are connected means of lifting rods b, bij, withseparatecrank wrists c c secured to a diskplate E to which a rockingmotien imparted by the eccentric F through the interventien oftheeccentricfrod d, and a crank f, securedvto the diskplate Theconnection of these exhaust valves with the crank `wrists of the diskplate and thence with the eccentric are permanent, and hence the exhaustvalves` will be alternately opened `and Aclosed with a regular movement,the epening ofone exhaust valve "being simultaneous `with, the

closing of the other. i

The armsgmgofthe steam valve rechi shafts terminatein toes' o, o, andareoperu ated by lifting rods it, it, which are pivoted to suitablecrank wrists e e uponthe disk plate These lifting rods terminate inhooks z' z', which engage with the toes o 0 j of the rockshaftarms, andare keptengaged with them by springs "j j which bear upon the backsofthe lifting rods; hence fas long as these hooks continue enga-ged`with the toes of the rock shaft arms the "steam valves close andthuscutoff` the passage ofr steam to ,t

the steam cylinder.` In order to elfectthis disengagement of the lifting'rods "which comniunicate` the l movement of the eccentric to the steam.valves,` each `rod"is littedilwith an adjustable stop 7c, le, againstwhichthe face of the rod bears in moving, and which j can be moved to`cause the hooked extremity of therod to detach itself from therespective toe ofthe rock shaft arm when the steam piston hasaccomplished any required portion of its stroke. These stops areconstructed to slide in blocks m, m, secured to the framework or otherconvenient portion of the engineg'their extremities bear against twoinclined blocks Z Z which are secured to a rod G, by raising or loweringwhich the stops are moved to effect the disengagement of the liftingrods when the piston has accomplished a less or greater portion of itsstroke. This sliding rod G in the examples represented in the drawing isconstructed to be moved by hand through the intervention of a rack n andworm 29,' the last of which is turned by hand to screw up or screw downthe sliding rod; but the sliding rod Gr may he moved by the engineitself, by connecting it with the slide of the gover nor so that as thelatter is moved the point at which the cut-off is effected will bevaried.

The inclined blocks, Z, Z, are of such form that when they are raised totheir highest positions, as at Fig. 3, the stops 7c 7c, will be so farprojected that the lifting rods, 7L, h, bearing upon them, will inmoving disengage from the toes of the rock shaft arms before the valveshave moved sufliciently to open their respective ports; while if theinclined blocks are depressed by the rod Gr to their lowest positions,as at Fig. 1, the stops, 7c, lo, will recede in their slide blocks, m m,sufficiently to have no action upon their respective lifting rods, andhence the latter will continue engaged with their respective toesthroughout the whole extent of the stroke. If the inclined blocks be setbetween these two extreme positions, as at Fig. 2, the stops will bemore or less projected, to detach the lifting rods sooner or later, asmay be required to regulate the amount of steam admitted to the steamcylinder.

In order to effect the closing of the steam valves after they aredisconnected from the eccentric gear, the rock shaft arms appertainingto each of them, has a weight r suspended from it by a rod s. Theseweights are sufficiently heavy to effect the instantaneous closing ofthe valve whenever its ap* propriate lifting rod is disengaged from thetoe of the rock shaft arm. In order to prevent the slam and jar thatwould result from the sudden closing of t-he valves, these weights arefitted to move easily in appropriate sockets formed, in the presentexample, in the bed ,plate of the engine. The weights moving in thesockets act as pistons to compress the air therein and thus retard theirdescent, and as air cushions to prevent the slam or jar. If thecompression of the air was continued throughout the whole descent` ofthe weight 'its motion would be too much .retarded to enablev it toclose the valvewith the requisitel speed; an orifice, t, Fig. l, 1stherefore made 1n each socket near its lower extremity to permit thefree entrance and thus cuts ofi' the escape of the air re-v maining inthe socket just before the valve closes its port, when the air, caught,or shut up in the socket, being compressed, will retard the furthermovement of the weight and will act as an air cushion to prevent theslam or jar.

When the stops are acting, the lifting rods are alternately disengagedin their inward movement toward the center of the disk plate, to allowthe valves to close under the action of, their respective weights, aseach lifting rod is moved outward, its extremity being pressed by itsappropriate spring y' against the toe of its respective rock shaft armis caused to rengage therewith in time to open the valve at thereturning rock of the disk plate in order to insure the closing of eachsteam valve before it is reopened a curved snug 'v is projected from theface of each lifting rod L, which in the outward movement of the latterwould strike against the lower side of the toe of the rock shaft arm andthus close the latter if by any accident it was not previously closed byits appropriate weight.

In order to lessen the wear of the toes and the hooks of the valve gear,their rubbing faces are faced with hardened plates of steel which whenworn can be readily replaced.

The arrangement of the lifting rods and the method of operating them bythe disk plate, as represented in the' accompanying drawings, ispeculiarly suited to this method of effecting the disengagement of thevalves from the mechanism by which they are opened, for the disk plateimparts a transverse motion to t-he connecting rods, which causes themto rock upon the stops and thus slide off their respective toes on therock shaft arms. But while I prefer this ar# rangement of eccentric gearI wish it to be understood that I do not restrict myself to itsemployment as my improvement may be ap'- plied to many othery systems ofmechanism by which valves are opened; as such systems may not possessthe peculiar rocking mot-ion I have mentioned, it will be necessary insome cases to disengage the lifting rods by a positive movement whichmay at the proper moment be imparted to the lifting rods by some movingmember of the engine through the intervention of any convenient andsuitable mechanical device.

I claim- In combination with the reciprocating motions communicated tothe lifting rods by the eccentric gear, I claim impartinga lateralmovement to the free extremities o-f said lifting rods to disconnectthem from .the

valves and permit the latter to close to cut off the steam or otherexpansive uid by `same more durable and less liable toget out 10 Whichtheengine may be driven, iwhereby `of order. n n

these rods are made to perform theirusual In testimony whereof I have`hereunto duty ofjopening the valves and in addition subscribed my name.that of catches or latches in alternately con- GEORGE CORLISS n neetingthe valves `with and disconnecting n them from the mechanism by Whichthey are Wvitnesses:

` opened, thus greatly simplifying the con- THOMAS A. GENERE, i

struction of the valve gear rendering the WM, 11 I-IENDERSOl`Tl i i i[FIRST PRINTED 1913.] i

